Question

if y varies inversely as x, find the inverse variation equation for the situations :

y=5 when x=4
AND
y=65 when x=9

Answer 1

y = a/bx

5 = a/4b + c
20 = a/b + 4c
20b - 4cb = a

65 = (20b - 4cb)/9b + c
585 = 20-4c + 9c
c = 113

20b - 4cb = a
20b - 452b = a
-432b = a

now you can choose whatever a and you will get the corresponding b..

y = a/bx + 113 , a = -432b